Usually, a digital storage oscilloscope has multiple input channels with each of the multiple channels capable of receiving an analog signal under test. Each of the multiple input channels has a respective analog-to-digital (A/D) converter to digitize the received analog signal under test into a stream of digital samples (or sample data) at a predetermined sampling rate. As known in the field, a digital storage oscilloscope includes an acquisition memory to store multiple streams of digitized samples to represent the analog signals under test. After accumulating enough digital samples in the acquisition memory, the digital storage oscilloscope re-assembles the received analog signals under test and displays them on its screen.
Even through the existing digital storage oscilloscopes generally meet the needs for certain applications, they have some shortcomings Specifically, in the existing digital storage oscilloscopes, the sampling rates and record lengths are same for all input channels that acquire and/or measure different input signals under test. It is usually impossible, or at least not flexibly, to share an acquisition memory among all input channels that acquire and/or measure different analog signals under test. The existing digital storage oscilloscopes can use two (or four) channels to acquire and/or measure one input signal with each of the two (or four) channels receiving a part of the data samples for the input signal and store the two (or four) parts of the sample data into the two (or four) memory areas that are allocated in the acquisition memory for the two (or four) channels. The existing digital storage oscilloscopes then re-assemble the one input signal based on the two (or four) parts of the sample data stored in the two (or four) memory areas of the acquisition memory. In this manner, the existing digital storage oscilloscopes can use so called “interleaving technology” to double (or quadruple) the sampling rate and record length for one active input channel by turning off the other one (or three) input channels, but “internally combining” the path(s) for the one (or three) inactive channels into the one active input channel. Even though the existing digital storage oscilloscopes can share multiple memory areas (unusually in even number) for one input signal, they are unable to proportionally allocate memory area(s) in an acquisition memory to the selected (or active) channels that acquire and/or measure different input signals under test, but not to allocate any memory areas in the acquisition memory for the non-selected (or inactive) channels. In other words, the existing digital storage oscilloscopes are unable to dynamically allocate memory areas in the acquisition memory for the selected (or active) channels that acquire and/or measure different input signals.
In addition, when its multiple input channels acquire and/or measure both slow and high frequency (or speed) signals, an existing digital storage oscilloscope defines its sampling rate in adapting to the signal with the highest frequency (speed). Therefore, in an existing digital storage oscilloscope, the acquisition memory resource assigned to an input channel that acquires a signal with slower speed may be unnecessarily large while the acquisition memory resource assigned to another input channel that acquires a signal with a faster speed is inadequate to re-assemble their respectively received signals.
Therefore, there is a need to provide improved signal acquisition display architecture in digital storage oscilloscopes that can flexibly share acquisition memory resources among multiple input channels that acquire and/or measure different input signals when one or more of the multiple input channels are not selected (or inactive).
There is another need to provide improved signal acquisition display architecture in digital storage oscilloscopes that can efficiently allocate acquisition memory resources among multiple input channels when the multiple input channels acquire and/or measure signals under test that have different frequencies (or speeds).